The chances of rescue by such a device might not be very brilliant, but it seemed the only thing left for him to do unless he were content to remain passively on the cage-buoy till he had to release his hold through sheer exhaustion.
The bell-buoy, he knew, was about a hundred yards distant, and in the daylight with a calm sea the swim would have amounted to nothing at all. But now the conditions were very different; he could not see the buoy and would have to guide himself entirely by the sound of the bell—added to which, the sea was rough, and he was still feeling exhausted from his recent struggle in the water. But, having decided that this was his sole remaining chance, Lawless did not hesitate and, first divesting himself of his heavy "lammys," slid into the water. The current dragged him right under the buoy, but after a struggle he managed to swim clear of it, and then struck out in the direction whence came the sound of the bell. At first he had little difficulty in making headway despite the choppy sea, but presently his stroke grew weaker, the muscles of his shoulders seemed as if they were on the point of cracking, and he found himself swallowing mouthfuls of salt water. A feeling akin to panic seized him, and he began to "dog-paddle" furiously, conscious only of a frantic desire to keep his head above the inky waves which descended upon him in an unending succession. For a moment or two he experienced all the horrors of approaching death by suffocation, and then, with a gigantic effort of will, threw off the numbing horror and struck out again with slow but steady strokes.
At last he caught sight of a dim, towering mass from whence came a harsh clang. He swam round it, and was lucky enough to encounter a large iron ring in the base, with the assistance of which he succeeded in dragging himself upon the narrow platform of the buoy. Here he remained for some moments lying on his chest, too exhausted to move. After a while, however, he recovered somewhat, though almost deafened by the clangour of the huge bell above his head. Tearing the woollen comforter from round his neck he climbed up to the bell and managed to wrap it round the clapper, thus effectually muffling it. This done, he slid down again and prepared to await whatever might happen.
It seemed to him that he had sat there for hours interminable, drenched by the waves and in peril of being washed off every moment, when he became aware of something grinding against his boots. He could not see what it was, but bending down felt with one hand and discovered a chain, which appeared to be attached to one of the ring-bolts round the base of the buoy.
"Now what the dickens is this for?" he asked himself.
A buoy, as he knew, is moored by chains attached to the bottom and not to the side, which would cause it to float askew. Besides, the chain grating against his boots was much too light to hold in position a mass weighing several tons and in weather such as this would have snapped like a thread. Therefore it was certainly not a mooring chain.
At the risk of slipping off the platform, Lawless twisted his legs round the pillar supporting the bell and, leaning forward, caught hold of the chain and tugged at it with both hands. It came in quite easily at first, and then stopped with an abruptness that nearly jerked the Lieutenant into the sea. He could see nothing, but passing one hand down the chain he felt something at the end—something large and buoyant, with sharp square edges like a box or a tank. Also he knew by the feel that it was metal.
Lawless forgot his own sufferings in contemplation of this puzzling discovery. What on earth, he asked himself, was the object of having a floating or submerged tank attached to this buoy? What did it contain? He pondered the matter for some minutes, and then, for the second time that night, had an inspiration.
It must be a secret petrol tank for the use of German submarines!
In a flash he divined the whole scheme. The bell-buoy, being such a well-known navigating mark, could not be mistaken for any other buoy in its vicinity. It was close to the English coast, and the tank attached to it could be replenished either by submarine petrol boats or by secret agents ashore—probably the former. On a dark night, such as this for instance, an enemy submarine could easily take on a fresh supply of petrol from the tank, while the latter, being submerged several feet below the surface, would not be seen in daylight. Doubtless, also, it was provided with an automatic arrangement whereby, when emptied of petrol, it became filled with sea-water, thus preventing it from floating on the surface and becoming visible. It was a most ingenious device, quite simple and, no doubt, an inestimable boon to belated enemy submarines which were running out of petrol. But the point was, having discovered this, how could he make use of it to the best advantage?